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The water cooled rack in a data center or equipment closet is now being classified as the most efficient means of transferring heat away from expensive equipment that may cost tens of thousands to replace if damaged. American Tech Supply as a leading rack supplier now carries a complete line of water cooled data cabinets and water cooled racks and carries the revolutionary water cooled data rack from Knurr and Emerson Network power for the ultimate in cooling and thermal temperature management for data cabinets and data centers with high temeperature requirements. The
advantages of the simple and safe water cooled data cabinet and water cooled rack previously outweigh the
disadvantage of the low heat transfer potential of gaseous coolants. In the
meantime, the heat load in high-performance servers has exceeded the options of
cost-effective cooling with air.
The CoolTherm® range of 'water-cooled server cabinets or water cooled data cabinets' can provide a great advance in data cabinet thermal management, reducing computer room costs, while improving operational performance and reducing facility operating costs.
Typical, high quantity conventional server cabinet layouts can effectively dissipate around 3.6kW each.

A single CoolTherm® 19" data cabinet or data rack will manage a 22kW heat load, enabling an 80% reduction in present, typical conventional cabinet numbers within large data centers. Resultant floor space savings of significantly reduce the take-up of large areas of expensive computer room floor, as server power levels skyrocket.
Cabinet installation costs can also be halved and enormous year-on-year operational savings made in associated reductions in CRAC install and running costs.Knürr CoolTherm® water cooled racks and water cooled data cabinets are completely sealed off from the room air. The dissipation of the total power loss is made via an air-to-water heat exchanger in the base area or door of the rack, which is connected to the cold water system in the building. Redundant high-performance fans drive a closed cold air circulation in the rack’s interior. The built-in servers are supplied from the front with air that is brought to the right temperature of about 20–25°C (68 °F to 77 °F). The warmed air is collected at the rear topside in the rack, pushed down by the heat exchanger and back to the front, to the server front panels. There are no requirements for room thermal management; the rack system is fully independent from the room air. Knürr AG with its global front position in thermal management research and development once again sets the high technology standard. The company consequently already provides a water-cooled server rack in series production today – the Miracel CoolTherm. This highly efficient system does not divert any heat loads to the surrounding environment. Instead, the entire energy is routed via the cold water system of the building infrastructure. The computer units in the server rack are supplied with cooled air from the heat exchanger. Trade standard servers can consequently be used and simultaneously combine the advantages of water cooling with low space requirements and high heat transport. With the optimised heat exchanger and air guidance systems, the CoolTherm attains up to 20,000 watts cooling power. Water cooled racks-FOR MORE INFO OR CONTACT US -PLEASE VISIT OUR CONTACTS PAGE

6U / 8U high performance heat exchanger

40 U / 38 U space for server; 37 U / 35 U can be used with DC fans

Canalized air flow through the enclosure

AC-distribution and DC-power supply in 3 U mounted on top of the servers

Alarm management: high temperature and fan failure alarms

Redundancy of DC power supply and of fans

Temperature controlled fan speed

6U / 8U high performance heat exchanger

40 U / 38 U space for server; 37 U / 35 U can be used with DC fans

Canalized air flow through the enclosure

AC-distribution and DC-power supply in 3 U mounted on top of the servers

Servers, storage and other IT components are constantly becoming more efficient
and at the same time more compact in their construction, and therefore require
less space. A computer centre’s infrastructure requirements will change dramatically, especially in tackling technical and physical heat load issues and in providing the thermal management needed to overcome these issues. Knürr has long been committed with high financial and time-consuming expense to the relevant individual solutions that the complexity of computer centres requires. Essential here is the awareness that this is not achieved just by developing and producing proven-in practice racks, but rather by focussing on the integrated view in providing solutions. The IT infrastructure is supported by five pillars: Racks, thermal management, power supply, mechanical security and monitoring of all parameters.The answer provided by Knürr’s dedicated engineers and industry experts features a diversity of solutions that manage the individual dissipated heat loads in their scalability of up to 35 kW per server rack – supported by innovative, future-proof and investment secured products from the Knürr portfolio (High Density Cooling Solutions Family).

The controlled airflow inside a relatively small enclosed space enables the evenly distributed cool air supply for all servers, regardless of their installation position in the rack. The top server is cooled exactly as much as the lowest.

The heat exchanger only requires 6 U per rack, which means that in a 46 U rack, 40 U remain for any kind of complete equipping with components. Apart from the heat exchanger, the user will find a perfectly normal 19” server rack. This means that there are absolutely no restrictions for installing components. Everything that can be installed in a conventional rack can also be located without change in the Knürr CoolTherm

These are generally intelligent thermal management concepts that function as component parts of an integral infrastructure concept. Knürr specialists are oriented in this respect towards the objective of providing availability with protection of investment, flexibility and modular expandability. Installation and operation of these solutions in computer centres, in the banking sector, automotive industry or in research and development for example, provide impressive examples of these features.

Call (866) 650-3282 or email us As the next development step for server cooling, Knürr presents a combined cooling system for CeBIT 2004. The new server rack is, as with CoolTherm, temperature-regulated with an air-to-water heat exchanger. In addition, the CPUs in the computing units and further high-performance chips, e.g. of the graphics processor, can be cooled directly with water. In this combined system, the user can avail of the maximum amount of cooling potential. The high “spot” heat loads of the processors are given off directly to the water-cooling circuit. Heat loads of 200 watt per processor can consequently be easily managed. The secondary heat loads of the server system, e.g. memory chipset, magnetic disc memory and power supplies are cooled with the temperature-regulated airflow. As the cool air used in the rack is temperature-regulated by a heat exchanger, no heat loads build up in the environment. The expensive room air-conditioning can be sharply reduced or even done away with.

An increase in power requirements will generate a proportional increase in heat. Greater densities and more powerful systems have driven up the power requirements in server cabinets. In some instances, the heat generated is more than the existing room air conditioning can handle. The option becomes increase the cooling capacity of the room or add cooling at the rack level. Although, more costly than standard racks, cooling cabinets can be a huge cost savings compared to retrofitting the cooling of an entire room.

As one of the most influential leading innovators in server rack and network technology, Knürr has already been consistently applying the industrial design as a strategic competition factor for many years.
A customer-specific industrial design and successful engineering are part of the core competencies and are incorporated into the Knürr integral quality concept. The top of the range product, CoolTherm®, a server rack platform equipped with innovative thermal management, continues this demand for high quality standards and is an expression of a highly creative value conservation and brand philosophy. Bestowal of the IF Award is recognition of this continuously implemented design strategy.

Future-Proof Solution in the Data Centre:
CoolTherm® Server, storage and IT components are constantly becoming more efficient and at the same time more compact in their construction, and increasingly require less space. The requirements of a data centre’s infrastructure are already undergoing drastic change, especially in order to provide thermal management to cope with the enormous increases in heat loads.
Knürr developed the CoolTherm®, a high quality product that has already been installed hundreds of times over and is primarily characterised by its integrated thermal management, as an innovative “future-proof” solution that is thermally managed separate from the room infrastructure by a closed air circulation in the CoolTherm® server rack. Even the airflow heated by blade servers to over 40°C is routed via an air-water heat exchanger and consequently efficiently cooled to 20 to 25°C, which allows an enormous dissipated heat load of up to 35 kilowatts to be managed. For the data centre and the IT room this concept represents a fail-safe, highly efficient and economical solution. Compared with a conventional cooling system, CoolTherm® achieves an 80% space saving and saves up to a quarter of the previous energy input for cooling. The CoolTherm® design formally emphasizes the innovative function of the heat exchange process and at the same time profiles the high quality rating of Knürr’s high-end product.

Water Cooled Data Cabinets

While high quantity conventional server cabinet layouts can effectively dissipate around 3.6 kW each, a single CoolTherm® 19" cabinet will manage a 22 kW heat load, enabling a massive 80% reduction in present, typical conventional cabinet numbers within large data centres.
Resultant floor space savings of 80% significantly reduce the increasingly high take-up of large areas of expensive computer room floor, as server power levels rocket.
Cabinet installation costs can also be cut by half, and enormous year-on-year operational savings can be achieved via associated reductions in computer room air conditioning install and running costs.
The water-cooled server cabinets use a building's readily available chilled water supply (6 to 12ºC range), connected into an air-to-water heat exchanger fitted in the base of each cabinet.
Sealed to IP54, the cabinets operate in their own controlled environment, independent of ambient room air. Closed-loop, temperature-controlled, redundant fan-blown air circulates within the cabinet, passing through the heat exchanger.
The cabinet is separated into two airflow areas (the cold and hot sides of the circulated air).

The CoolTherm® is available with cooling capacities of between 10 and 35 kW in steps of 2.5 kW
(Spread chilled water: 12/22°C) .
There is hardly any requirement for capacities below 10 kW, but it requested, smaller capacities can also be catered for at any time.

Are any special components (especially servers) required for CoolTherm®?

All components that are used in a conventional rack can be used in the CoolTherm® without restriction. The servers are freely accessible from the front and rear, as with a normal rack.

Can heat volume diversion be controlled in accordance with heat loss?

The heat dissipation basically controls itself, with lower cooling requirements only the air output temperature from the heat exchanger is reduced. With use of controlled DC fans, the air circulation volume is adjusted to the respective cooling requirement and the power consumption of the system is consequently minimised.

How is the airflow routed in the rack and what advantages does this provide?

The heat exchanger installed on the lowest level of the rack blows the cooling air with a temperature between 20 and 25 °C from below to the front of the server. Each server takes in its cooling air from the front and releases it to the rear with a temperature increased by approx. 10 K. The heated air is in turn sucked up behind the servers and pushed with two fans through a channel in the rear door down into the heat exchanger.
Advantages:
- Closed air circulation
- Clear airflow with minimum flow diversions
- Same length flow paths through all servers
- Flow guidance supported with thermal buoyancy
- Very high cooling capacity on the smallest installation space

Are the servers cooled equally over the entire rack height or are the higher racks cooled less?

Because of the type of airflow (see above) and the high surrounding air volume, all servers are equally supplied with cooling air from the front, even with irregular load distribution over the height. The construction of the rack prevents heated air from the rear reaching the front without being cooled.

Can the CoolTherm® be operated with opened doors?

With fully opened doors the back-cooled air from the heat exchanger is then given off to the room from which the servers and other components take in their cooling air. No heat is given off into the room.
The rear door can be only briefly opened during operation as the cooling air circulation is consequently interrupted and the dissipated heat is given off into the room.

Why did Knürr decide to position the heat exchanger on the rack bottom cover and not on the roof or in one of the side or rear panels?

The main reason for this is the consequential securing of the system against leakage risks. Water-carrying components are exclusively positioned with CoolTherm® on the lowest level of the rack where the connection to the cooling water system is made. Even with a leakage (which is highly improbable), water can never reach the electronic components. Positioning on the roof is therefore ruled out in every case.
This argument also applies with add-on on the side or in one of the doors, if perhaps, with limits.
One argument against add-on on the side panel is the fact that the rack no longer fits into the spacing of the rack suites in the computer centre because of its considerably increased width.
Overall, installation on the lowest level of the rack is the most compact, most cost-efficient and safest solution.

How is the water connected to the Knürr CoolTherm® racks?

The connection to the building system is made from below via the standard screw-fitting techniques tried, tested and proven in building mechanics.

Can air-cooled and water-cooled server racks be operated beside one another in a computer centre?

The racks are fully compatible in their dimensioning without any further requirements. For water-cooled racks only the cooling water installation must be available.

Two fans are installed in the CoolTherm®.
Can one fan also cope with the required determined nominal heat load?

The fans are installed redundantly, i.e. one alone is sufficient to operate the system at full capacity. Only the internal rack temperature rises insignificantly here (a few degrees).

Do Knürr CoolTherm® racks have to be maintained?

The CoolTherm® is maintenance-free. All components are installed with a very long lifespan. The fans are speed-controlled; if a fan fails, the corresponding information is passed through the network. The system can be fully operated with one fan when making exchanges.

What advantages does a water-cooled solution provide in the computer centre when compared with an air-cooled solution?

Use of water-cooled racks enables installation and alignment of high-performance servers and server racks with the highest possible packing densities, even for higher cooling capacities above 4-6 kW per rack. This results in very significant savings with investment costs and the operating costs of a computer centre. For details and exact values, see TCO* study of March 2004.
*) TCO = Total Cost of Ownership

Is a raised floor required for the installation?
If yes, what is the necessary height?

A raised floor is not required for routing the cooling water pipes, the pipes can basically also be installed in channels in the bottom cover.
A main cooling pipe in a raised floor requires approx. 150 mm; a rack feed requires approx. 50 mm installation height. With high-grade multitubes, as they are used in floor heating for example, a very flexible laying of cooling water lines is possible.

Can CoolTherm® racks also be connected in series alongside one another?

Without restriction, just as with conventional server racks.

How is the dew point build-up/condensation build-up prevented in the CoolTherm® system?

Condensation build-up with passing below the dew point can only occur at the coldest points in the rack, which are the cooling surfaces in the heat exchanger. The heat exchanger is configured so that any possible condensation of the airflow is removed and diverted.

Is it ensured that the air volume required for the cooling is also available in the rack?

As even an IP 55 rack is not vacuum-tight, a pressure balance occurs between the surroundings and the rack interior. The rack is consequently completely filled with air. The cooling capacity depends on the air quantity circulating inside the rack, which is ensured by the corresponding configuration of fans and heat exchangers.

Can the Knürr CoolTherm® structure system also be operated together with the Knürr CPU cooling solution?

With very high performance losses of a CPU ( >100 W, for example), the air cooling of the CPU in the server becomes problematic, especially in servers with very low installation spaces, such as Blade or Pizzabox servers. In cases such as this, the CPUs should be cooled directly with water.
A combination with the CoolTherm® rack cooling is possible at all times as only approx. 50-60% of the entire dissipated heat of a server is diverted per CPU cooling; with higher cooling capacities this is even necessary.

How is water prevented from causing faults in the rack in the event of a pipe break?

Careful selection of the components practically prevents the possibility of a pipe breaking. Should a leak nevertheless occur in the cooling water system in the rack, the positioning of all water-carrying parts on the lowest level of the rack ensures that water can never reach above this level in the server.
A water sensor is also offered as an option, with which even the smallest leaks can be detected immediately.

Why do Knürr not offer a 2-rack solution, i.e. the combined cooling of two racks with one air/water heat exchanger as is provided by other manufacturers?

Can an already installed CoolTherm® system be upgraded for higher capacity ranges?

Depending on the required capacity jump with adjusting of the control software, rear door (fan) or heat exchanger can be swapped out.

Is the CoolTherm® solution already running in operational use?
If yes, are there references for this?

The worldwide first computer centre equipped with autonomous water-cooled server racks, GridKa at the Karlsruhe Research Centre, was put into operation with CoolTherm®. Since autumn 2003, 1,300 high-performance servers have been working in productive operation in 35 racks. The installed cooling capacity is currently 350 kW with expansion by factor 3. The planned overall cooling capacity will be over 1 MW.

For what applications and situations should I use water-cooled structure systems?

Always when the cooling capacity of the room air-conditioning is not sufficient to cope with today’s high-performance servers.
With an optimum configuration in recently planned computer centres the limit here is at approx. 1,000 – 1,200 W/m²; in older computer centres this is often well below this, whereby a maximum 4 kW can be coped with per rack in the best case scenario. Racks fully packed with Blade servers by contrast can already achieve 17 kW today. The solution to deal with this could be to only load racks to a quarter of their spatial capacity – or to use Knürr CoolTherm® liquid-cooled server racks.

What additional infrastructure is required along with the rack and the corresponding pipes in order to be able to operate the system?

The required infrastructure corresponds for the most part with the infrastructure already used in conventional thermally managed computer centres. The “colds” (n+1 redundant) generate cold water systems (chillers) that are distributed over the cooling water system in the computer centre on air circulation refrigeration equipment or even on ceiling cooling equipment.
The only additionally required component is the pipe routing to the individual racks, which is installed flexibly and cost-effectively with the use of high-tech plastic pipes.

What basic disadvantages of the current air-cooled solutions are removed by water cooling?

The main problem with conventional cooling is the routing of very large cooling air volumes through raised floors, hanging ceilings and inside rooms. The water cooling assumes the task of carrying out the critical heat transport through these areas. As water can transport 3,500 times as much heat per volume as air can, very small lines are sufficient for transporting very large heat volumes.
Cooling with air is not problematic in a rack with clear airflow inside a closed-off space.

Can accessories and other equipment from the 19” superstructure racks also be used in the CoolTherm®?

The installation conditions in the CoolTherm® are no different than those of the standard air-cooled 19” racks. All components and accessory parts can be used without restriction.

Do Knürr have the necessary certificates for operation and performance of this system?

There are still no special standards for liquid-cooled server racks, therefore there are also no certificates. As a pioneer in this area, Knürr have equipped the first operative computer centre with CoolTherm® racks and has the required know-how and the required equipment (thermo simulation, climatic test chamber) to guarantee the performance, security and reliability of the system. The rack does of course meet all existing relevant standards for conventional racks.

Where can I find out more about the CoolTherm® solution or about the requirements of water-cooled systems or the “musts” for water-cooled systems?

The best place to look is in the new Knürr brochure on liquid cooling, in printed form or on the Knürr website.

Are there options for testing very specific heat/heat loss situations in preliminary stages?

Knürr can “tailor make” solutions to meet every conceivable requirement right from the very first step, both with thermo simulation and by testing in climatic test chambers.

How can I convince my company/OU of the advantages of a water-cooled solution?

We carry cable management racks, Wallmount Rack and wallmount rack solutions for applications ranging from data centers, server rooms, to all office envrironments. Not only will ATS will meet or beat all US based pricing- but will assist you in designing your network at NO EXTRA CHARGE. Call us for details at (866) 342-3721.